In treating diseases of various body organs, it is necessary to deliver drugs or other agents to the organs at specified locations. Most common routes of drug delivery include a non-invasive peroral (through the mouth), topical (skin), transmucosal (nasal, buccal/sublingual, vaginal, ocular and rectal) and inhalation routes. However, many therapeutic agents, such as peptide and protein, antibody, vaccine and gene based drugs, in general may not be delivered using these routes because they might be susceptible to enzymatic degradation or cannot be absorbed into the systemic circulation efficiently due to molecular size and charge issues, and thus, will not be therapeutically effective. For this reason, many such drugs have to be delivered by injection.
Often, it is necessary to deliver medicinal or therapeutic substances to remote and tortuous blood vessels and other lumens within body organs, such as lungs. It is also important to be able to deliver defined doses of therapeutic and diagnostic substances because such substances are often very expensive or are capable of causing serious harm if delivered in excess. Several devices have been proposed for a targeted delivery of drugs to internal bodily cavities.
For example, U.S. Pat. No. 6,309,370 to Haim et al. describes an apparatus for intracardic drug administration, including a catheter which is inserted into a chamber of the heart. The catheter includes a drug delivery device having a needle positioned within the catheter's distal end and a drug dispenser connected to the needle via a duct. The drug delivery device further includes a displacement mechanism, preferably a hydraulic piston, which drives the needle distally out of the distal end of the catheter to administer the drug.
U.S. Patent Publication No. 2007/0038181 to Melamud et al. describes a device for delivering a substance to organs, particularly the bladder. The device includes a delivery tube, a chamber to be filled with the substance to be delivered, a plurality of needles, and a plunger coupled to a handle movable relative to the tube to deliver the substance through the needles.
U.S. Pat. No. 6,004,295 to Langer et al. describes a catheter assembly for injecting therapeutic liquids into a patient's myocardium. The catheter assembly comprises an elongated catheter, a reservoir for therapeutic liquid positioned at a distal end of the catheter, one or more injection needles protruding from the distal end of the catheter in fluid communication with the reservoir and a hydraulic syringe for delivering the therapeutic liquid from the reservoir through the needles.
However, the known drug delivery systems such as those described above suffer from a number of disadvantages and shortcomings. For example, the prior art delivery systems are usually specifically adapted for delivering drugs to particular body organs, and therefore are unsuitable for use on a variety of internal organs and tissues. Additionally, the prior art devices are incapable of delivering therapeutic or medicinal fluids in precise quantities. Furthermore, known delivery devices are complex, bulky and difficult to introduce into remote locations within a patient's body, e.g. lungs.
What is desired, therefore, is a drug delivery system and method that overcomes the problems of known prior art drug delivery devices. It is also desired to provide a drug delivery device that allows for accurate delivery of medicinal and therapeutic substances to remote and not easily accessible locations in a patient's body. It is further desired to provide a device capable of delivering precise quantities of a drug to a desired internal organ or tissue, as well as enabling the application of various electrodes and/or probes for measuring certain tissue characteristics, such as oxygen concentration in the tissue. It is also desired to provide a delivery device that is efficient and that can be manufactured at a relatively low cost.